1. Field of the Invention
The present invention relates to a radio terminal device, and more particularly to a radio terminal device having an improved antenna characteristic.
2. Description of the Related Prior Art
In recent years, a radio terminal device such as a cellular phone and the like has a high-performance communication characteristic and is small-sized and thin-sized.
A user makes its head close to a radio terminal device when using the device. The human head has a characteristic of having an influence on a radio wave. Due to this, when a user uses a radio terminal device, the head of a user has an influence on the communication characteristic of a radio terminal device. The communication characteristic of a small-sized and thin-sized radio terminal device is greatly influenced by a human head. Therefore, design of a radio terminal device, particularly design of an antenna must be performed so as to reduce the influence by the human head. Japanese Utility Model Publication No. 3,035,683 has disclosed a cellular phone being provided with an electrically conductive surface coated with a conductive material all over the internal surface of its enclosure. This cellular telephone prevents its transmission and reception characteristics from being subject to electrically influence from the outside by shielding the whole enclosure. However, since the antenna of this cellular phone is arranged outside the enclosure, it is liable to be subject to various influences.